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    \title{Folksonomies - Cooperative Classification and Communication
    Through Shared Metadata}

    \author{
      Adam Mathes \\
      Computer Mediated Communication - LIS590CMC\\
      Graduate School of Library and Information Science\\
      University of Illinois Urbana-‍Champaign\\
      }
      \date{December 2004}
    \maketitle
  

    
    \begin{abstract}
  
      
\par This paper examines user-‍generated metadata
      as implemented and applied in two web services designed to share
      and organize digital media to better understand grassroots
      classification. Metadata - data about data - allows systems to
      collocate related information, and helps users find relevant
      information. The creation of metadata has generally been
      approached in two ways: professional creation and author
      creation. In libraries and other organizations, creating
      metadata, primarily in the form of catalog records, has
      traditionally been the domain of dedicated professionals working
      with complex, detailed rule sets and vocabularies. The primary
      problem with this approach is scalability and its impracticality
      for the vast amounts of content being produced and used,
      especially on the World Wide Web. The apparatus and tools built
      around professional cataloging systems are generally too
      complicated for anyone without specialized training and
      knowledge. A second approach is for metadata to be created by
      authors. The movement towards creator described documents was
      heralded by SGML, the WWW, and the Dublin Core Metadata
      Initiative. There are problems with this approach as well -
      often due to inadequate or inaccurate description, or outright
      deception. This paper examines a third approach: user-‍created
      metadata, where users of the documents and media create metadata
      for their own individual use that is also shared throughout a
      community.\end{abstract}
  

    
      \section{The Creation of Metadata: Professionals, Content Creators,
      Users}
  

      
\par Metadata is often characterized as ``data about data.''
      Metadata is information, often highly structured, about
      documents, books, articles, photographs, or other items that is
      designed to support specific functions. These functions are
      usually to facilitate some organization and access of
      information. Administrative, structural, and descriptive
      metadata are three broad categories of metadata (Taylor,
      2004). This paper focus primarily on descriptive metadata which
      identifies and functions to organize information based on its
      intellectual content.

      
\par Traditionally metadata is created by dedicated
      professionals. Catalogers create metadata, often in the form of
      Machine-‍Readable Cataloging (MARC) records for books and other
      intellectual creations, and this is the basis of most Online
      Public Access Catalogs (OPAC) in libraries and other
      institutions. This often requires serious education and
      training. The library and information science field has
      developed elaborate rules and schemes for cataloging,
      categorization and classification that include classification
      schemes such as the Dewey Decimal System and Library of Congress
      Classification Scheme, as well as large controlled vocabularies
      of terms for describing the subject of materials, such as the
      Library of Congress Subject Headings.

      
\par While professionally created metadata are often considered of
      high quality, it is costly in terms of time and effort to
      produce. This makes it very difficult to scale and keep up with
      the vast amounts of new content being produced, especially in
      new mediums like the World Wide Web.  An alternative is author
      created metadata. Original creators of the intellectual material
      provide metadata along with their creations. The Dublin Core
      Metadata Initiative has been used with some success in this area
      (Greenberg et al, 2002). Author created metadata may help with
      the scalability problems in comparison to professional metadata,
      but both approaches share a basic problem: the intended and
      unintended eventual users of the information are disconnected
      from the process.

      
\par User created metadata is a third approach, and this paper
      focuses on grassroots community classification of digital
      assets. Other forms of user created metadata are often
      implicit. Citation analysis is a well established technique used
      to determine relationships between academic works and the impact
      of scholars. Similar analysis of the link structure in the World
      Wide Web is used by the PageRank algorithm, which became the
      theoretical basis for the Google search engine (Page,
      1998). Recommendation systems, and those that employ
      collaborative filtering are another form of leveraging implicit
      user created metadata. (Lieberman, 2002).

      
\par One form of explicit user created metadata was popularized in
      the late 1990's with link-‍focused websites called weblogs (Blood
      2000). These sites provide links combined with commentary, and
      are a form of mostly unstructured, but explicit, user created
      metadata.  Customer reviews on web sites such as Amazon.com are
      an integral aspect of online commerce, and leverages consumer
      created metadata to create sites that are far more informative
      than comparable commercial sites. 
    

    
      \section{Tagging Content in Del.icio.us and Flickr}
  

      
\par Del.icio.us (http://del.icio.us, henceforth
      referred to as ``Delicious'') is a tool to organize web pages. A
      description online states it is: 

      
\par ``a social bookmarks manager. It allows you to easily
      add sites you like to your personal collection of links, to
      categorize those sites with keywords, and to share your
      collection not only between your own browsers and machines, but
      also with others'' (Schachter, 2004)

      
\par Delicious is not unique or pioneering in its role as
      bookmarks manager. What seems to be relatively new and different
      is the emphasis on user added keywords as a fundamental
      organizational construct. These keywords, which are referred to
      as ``tags'' on the site, allow users to describe and organize
      content with any vocabulary they choose.

      
\par To use the system, you must first join by registering an
      account. The system is free to join and use. Only a username,
      full name, and password are required. The user then adds a
      specialized bookmark to their web browser. When browsing a web
      page they would like to add to delicious, they select the
      bookmark, and are presented with a form that has allows them to
      enter any tags they want to associate with the page, and then
      save it. These tags are optional; users can and do use the site
      without tagging their documents.

      
\par In addition to automatically generated chronological ordering
      of bookmarks saved to the system, the tags are used to collocate
      bookmarks within a user's collection. Additionally, these tags
      are also used to collocate bookmarks across the entire system,
      so for example, looking at the page http://del.icio.us/tag/linux
      will show all bookmarks that are tagged with ``linux'' by any
      user.

      
\par Flickr (http://www.flickr.com), a photo
      management and sharing web application, has a similar system of
      free-‍form tagging for photos that was adopted and modeled after
      Delicious. It too requires users to create a user account, and
      is free to join. There is also the option to pay for an account
      with more features, like more storage space for
      photographs. Flickr offers a similar bookmark to add photographs
      to the system, but also has a number of other options to upload
      photographs to the system through web pages and software
      applications. Tags can be added at the time of upload, or later
      in the process when the photographs are displayed by the
      system.

      
\par A primary difference between Delicious and Flickr is that
      while the tags on Delicious are primarily from the users of web
      documents that were written by another party, Flickr is
      primarily used by individuals to manage their own digital
      images, and the majority of the tags are users tagging photos
      they created themselves. This is not absolute; the system does
      have the option of allowing users designated as friends or
      family to tag a users' photos. Additionally, users can and do
      enter images others created into the system, often from web
      sites. This use of the system is much more like Delicious, but
      seems to be a small fraction of the use.
    
    
      \section{From Tags to Folksonomy}
  

      
\par The most popular tags used on Delicious are listed on the
      right side of the front page. Related tags, as determined
      programmatically by the system, are listed on the right side of
      individual tag pages. The organic system of organization
      developing in Delicious and Flickr was called a ``folksonomy'' by
      Thomas Vander Wal in a discussion on an information architecture
      mailing list (Smith, 2004). It is a combination of ``folk'' and
      ``taxonomy.''

      
\par An important aspect of a folksonomy is that is comprised of
      terms in a flat namespace: that is, there is no hierarchy, and
      no directly specified parent-‍child or sibling relationships
      between these terms.  There are, however, automatically
      generated ``related'' tags, which cluster tags based on common
      URLs. This is unlike formal taxonomies and classification
      schemes where there are multiple kind of explicit relationships
      between terms. These relationships include things like broader,
      narrower, as well as related terms. These folksonomies are
      simply the set of terms that a group of users tagged content
      with, they are not a predetermined set of classification terms
      or labels.

      
\par In Delicious, a cursory analysis of the tags reveals that the
      most popular tags are primarily subject descriptor keywords at
      various levels of specificity. Some of the most popular tags (as
      of November 14, 2004) according to the system were: ``software,
      design, programming, music, politics, web, news, blog, css,
      linux, art, osx, java, mac, blogs, reference, fun, python,
      games, tech, photography, humor, tools, delicious, rss, firefox,
      toread, comics.'' Many of these are technical subject tags
      reflecting the common interests of a tech-‍savvy user base,
      e.g. ``rss, firefox, python, java, linux.'' Some are best
      described as genre or form descriptors, like ``comics, humor,
      fun, photography.''  At least one, ``toread,'' is something
      qualitatively different: it is a tag apparently used for
      self-‍organization and reminder.  Similarly, ``wishlist'' (http://del.icio.us/tag/wishlist)
      was apparently used by a number of users to highlight consumer
      items they were interested in.

      
\par The 150 most popular tags on Flickr are tabulated and listed
      on the site. As of November 19, 2004, this list included much of
      what one might expect as common subjects of photos: cat,
      friends, dog sky, sea, park, kids, garden, baby, building,
      flower, flowers signs, sculpture, city, vacation. Over 25\% (41
      out of 150) of the tags were proper place names like cities or
      countries. Colors were listed: yellow, green, blue, pink,
      orange, white, red. Years were also popular as tags, 2001, 2002,
      2003 and 2004 were present amongst the most popular.

      
\par Some terms that have particular meaning in the photographic
      domain like portrait, macro, landscape, blackandwhite were
      included. The terms ``cameraphone, moblog, fotolog'' reflect the
      use of relatively new words, and the connection the site has to
      tech savvy early adopters of integrated camera phone technology
      and weblogs focused on photographs.

      
\par Two tags of particular interest are ``cute,'' and ``me.'' This
      will be elaborated upon later, but I think these two terms
      reflect the dual nature of these systems: the compulsion to
      share - what is the Internet if not a venue for
      sharing cute photographs? - and conversely the importance of
      individuality and ego for these systems to work.

      
\par Overall, although the term ``classification'' is often used in
      relation to these systems, and has been used in this paper, what
      is going on is more like ``categorization.'' Categorization is
      generally less rigorous and boundaries are less clear. It is
      based more on a synthesis of similarity than a systematic
      arrangement of materials (Jacob 2004). Most importantly, each
      document can have many terms associated with it. By contrast,
      classification schemes generally focus on providing a single
      classification to an item, and are very hierarchical and have
      clear relations. In a folksonomy the set of terms is a flat
      namespace: there are no clearly defined relations between the
      terms in the vocabulary.

      
	\subsection{Limitations}
  

	
\par The problems inherent in an uncontrolled vocabulary lead to
	a number of limitations and weaknesses in
	folksonomies. Ambiguity of the tags can emerge as users apply
	the same tag in different ways. At the opposite end of the
	spectrum, the lack of synonym control can lead to different
	tags being used for the same concept, precluding
	collocation.

	
	  \subsection{Ambiguity}
  

	  
\par As an uncontrolled vocabulary that is shared across an
	  entire system, the terms in a folksonomy have inherent
	  ambiguity as different users apply terms to documents in
	  different ways. There are no explicit systematic guidelines
	  and no scope notes. For example, items tagged with
	  ``filtering'' on Delicious included the following:

	  \begin{itemize}
  \item Last.FM - Your personal music network - Personalized
	    online radio station\item InfoWorld: Collaborative
	    knowledge gardening\item Wired 12.10: The Long
	    Tail\item Oh My God It Burns! `` Practical Applications
	    of the Philosopher's stone. For drunks. Brita filter makes
	    bad vodka into good vodka\item Introduction to
	    Bayesian Filtering
    \end{itemize}
  

	  
\par These are all ``filtering,'' but in very different
	  senses. Using water filters to purify vodka is a very
	  different subject than Bayesian statistical analysis.

	  
\par Acronyms present another area of potential ambiguity that
	  are often dealt with effectively in controlled
	  vocabularies. Examining the front page on November 14, 2004
	  revealed one user tagging sites with ``ANT.'' After examining
	  the other sites the user tagged with ANT, it was apparent
	  this was an acronym for ``Actor Network Theory,'' in the
	  domain of sociology. However, when examining the ANT tag
	  across all users (Delicious apparently is not case sensitive
	  in tags) most of the bookmarks were about Apache Ant, a
	  project building tool in the Java programming language. Two
	  completely separate domains and ideas are mixed together in
	  the same tag.
	

	
	  \subsection{Spaces, Multiple Words}
  

	  
\par Both Delicious and Flickr seem designed primarily to deal
	  with single words. Delicious does not allow spaces in tag
	  names, although Flickr does. In some instances, multiple
	  words are used together in a single tag, without spaces,
	  i.e., ‘vertigovideostillsbbc' on Flickr. At times this can
	  reflect users trying to put a hierarchy into a single tag,
	  or simply reflects a category that has multiple terms, such
	  as ‘design/css' on Delicious. (http://del.icio.us/tag/design/css.)
	  Both systems ignore letter case, which may collapse distinct
	  ideas into a single tag, especially with acronyms.
	

	
	  \subsection{Synonyms}
   
\par There is no synonym control in the
	  system. This leads to tags that seemingly have similar
	  intended meanings, like ``mac,'' ``macintosh,'' and ``apple'' all
	  being used to describe materials related to Apple Macintosh
	  computers. Different word forms, plural and singular, are
	  also often both present. In this particular situation with
	  these Macintosh tags, the ``related tags'' sidebar of
	  Delicious interlinks all three of these categories
	  automatically. Plural vs. singular is often a problem, as
	  seen in the popular tags on Flickr, both ``flower'' and
	  ``flowers'' were listed.

	  
\par These sorts of problems are the reasons why controlled
	  vocabularies are used in many settings. Generally, any of
	  the classic problems that controlled vocabularies help deal
	  with will be present in these systems to varying
	  degrees. However, it is likely that a controlled vocabulary
	  would be impossible in the context of systems like Delicious
	  and Flickr.
	  
	
      
      
	\subsection{Strengths}
   
\par Although a folksonomy is not a
	controlled vocabulary, and certainly does have limitations,
	there are important strengths that are important to
	understanding the appeal and utility of such systems.
	
	
	  \subsection{Browsing vs. Finding}
   
\par The first is
	  serendipity. While the controlled vocabulary issues
	  discussed above may hamper findability, browsing the system
	  and its interlinked related tag sets is wonderful for
	  finding things unexpectedly in a general area. In
	  researching this paper, exploring the bookmarks tagged with
	  ``folksonomy'' on Delicious, there were many recent resources
	  from a wide variety of authors and sites that I likely would
	  never have been exposed to.
	  
	  
\par There is a fundamental difference in the activities of
	  browsing to find interesting content, as opposed to direct
	  searching to find relevant documents in a query. It is
	  similar to the difference between exploring a problem space
	  to formulate questions, as opposed to actually looking for
	  answers to specifically formulated questions. Information
	  seeking behavior varies based on context. While one could
	  evaluate a folksonomy in a system like Delicious or Flickr
	  by using specific queries from users, and then evaluating
	  which documents tagged with keywords they choose are
	  relevant to the query, that would ignore the broader set of
	  browsing activities that the system seems to be stronger
	  in. Measuring the utility of that aspect would likely
	  require qualitative research in the form of interviews or
	  ethnographic study of users, and is an area of further
	  study. It would also require comparisons not to search based
	  information retrieval systems, but to browsing activities
	  using other categorization and classification schemes.
	  
	
	
	  \subsection{Desire Lines}
   
\par Perhaps the most important strength
	  of a folksonomy is that it directly reflects the vocabulary
	  of users. In an information retrieval system, there are at
	  least two, and possibly many more vocabularies present
	  (Buckland, 1999). These could include that of the user of
	  the system, the designer of the system, the author of the
	  material, the creators of the classification scheme;
	  translating between these vocabularies is often a difficult
	  and defining issue in information systems. As discussed
	  earlier, a folksonomy represents a fundamental shift in that
	  it is derived not from professionals or content creators,
	  but from the users of information and documents. In this
	  way, it directly reflects their choices in diction,
	  terminology, and precision.
	  

	  
\par Some classification schemes are disjoint from the
	  vocabulary of the users. In ``Metadata for the Masses,'' Peter
	  Merholz argues that a folksonomy can be quite useful in that
	  it reveals the digital equivalent of ``desire lines''
	  (Merholz, 2004). Desire lines are the foot-‍worn paths that
	  sometimes appear in a landscape over time. Merholz notes, ``A
	  smart landscape designer will let wanderers create paths
	  through use, and then pave the emerging walkways, ensuring
	  optimal utility. Ethnoclassification systems can similarly
	  ‘emerge.' Once you have a preliminary system in place, you
	  can use the most common tags to develop a controlled
	  vocabulary that truly speaks the users' language.''
	  

	  
\par Merholz recommends using a folksonomy as the start of
	  professionally designed controlled vocabularies. While this
	  may not be practical or desirable in many situations, the
	  fundamental point is that the vocabulary of users may simply
	  be too different from the other parties to adequately ``pave
	  the paths'' in advance. Another important point may be that
	  the terms users want to use move too quickly, or are
	  qualitatively different than authors or systems designers.
	  

	  
\par Merholz's own piece provides an excellent
	  example. Merholz does not use the term ``folksonomy.'' He has
	  written on his personal web site that the term is inaccurate
	  due to its derivation from ``taxonomy,'' which he argues tend
	  towards hierarchy and control. (Merholz, 2004) (See also
	  Taylor, 2004, for discussions of problems and disputes with
	  the term ``taxonomy.'')  Merholz prefers the term
	  ``ethnoclassification,'' which is what he uses in his article,
	  and there is no mention of ``folksonomy'' to be
	  found. Ethnoclassification is also inaccurate, because as
	  discussed, what is happening is quite unlike classification
	  and far more like categorization.
	  

	  
\par Despite Merholz's personal preference as author, his
	  piece is tagged on Delicious with both ``ethnoclassification''
	  and ``folksonomy,'' as well as various other tags including
	  ``userexperience,'' ``tagging,'' ``taxonomy,'' ``metadata,''
	  ``socialsoftware,'' and ``facets.'' The tags reflect not the
	  author's vocabulary, or any particular classification or
	  categorization system's vocabulary, but the language and
	  vocabulary that individual users choose to describe the
	  article with.
	  

	  
\par Although the Delicious tags on Merholz's article are only
	  one example, a folksonomy, with its uncontrolled nature and
	  organic growth, has the capability to adapt very quickly to
	  user vocabulary changes and needs. There is no significant
	  cost for a user or for the system to add new terms to the
	  folksonomy. The problem is that while the disparate user
	  vocabularies and terms enable some very interesting browsing
	  and finding, the sheer multiplicity of terms and
	  vocabularies may overwhelm the content with noisy metadata
	  that is not useful or relevant to a user.
	  
	
      
    

    
      \section{Why Folksonomies Work}
  

      
\par It is difficult to define a metric by which one could argue
      folksonomies are a success or failure, but the degree that it
      does seem to be effective in these systems as a way or
      organizing information, and that a large group of people are
      using these systems, I posit, is due to a few important
      factors. The overall costs for users of the system in terms of
      time and effort are far lower than systems that rely on complex
      hierarchal classification and categorization schemes. In
      addition to this structural difference, the context of the use
      in these systems is not just one of personal organization, but
      of communication and sharing. The near instant feedback in these
      systems leads to a communicative nature of tag use.

      
	\subsection{Barriers to Entry, Cognitive Costs}
   
\par The conceptual
	shift from professional, designed, clearly defined
	categorization and classification schemes to an ad-‍hoc set of
	keywords enables users — not just professionals — without
	any training or previous knowledge to participate in the
	system immediately. Additionally, participating is far easier
	in terms of time, effort and cognitive costs.
	

	
\par Stewart Butterfield, one of the creators of Flickr, argues
	that the difference in complexity between folksonomies and
	classification schemes is important:
	

	
\par ``Aside: I think the lack of hierarchy, synonym
	control and semantic precision are precisely why it
	works. Free typing loose associations is just a lot easier
	than making a decision about the degree of match to a
	pre-‍defined category (especially hierarchical ones). It's like
	90\% of the value of a ‘proper' taxonomy but 10 times simpler.''
	(Butterfield, 2004)
	

	
\par Many professionals would likely argue that Butterfield's
	assessment of 90\% and ``10 times simpler'' is vastly overstated,
	his fundamental point holds true: non-‍trivial and important
	metadata are captured through these folksonomies. The
	comparisons are almost irrelevant as it would be impossible to
	get the users of these systems to use a complex, hierarchical,
	controlled vocabulary. The barriers are simply too high. A
	system that tried to capture that full value would cost too
	much in user time, effort, and cognitive cost, and thus have
	little value in practice.
      

      
	\subsection{Feedback and Asymmetric Communication}
   
\par Jon Udell
	(2004) argues that the idea of abandoning taxonomy in favor of
	lists of keywords is not new, and that the fundamental
	difference in these systems is feedback.
	

	
\par ``Of course, that idea's been around for decades,
	so what's special about Flickr and del.icio.us? Sometimes a
	difference in degree becomes a difference in kind. The degree
	to which these systems bind the assignment of tags to their
	use - in a tight feedback loop - is that kind of difference.
	

	
\par Feedback is immediate. As soon as you assign a tag to an
	item, you see the cluster of items carrying the same tag. If
	that's not what you expected, you're given incentive to change
	the tag or add another. If your items aren't confidential and
	online-‍only access is sufficient, this can be a great way to
	manage personal information. But the real power emerges when
	you expand the scope to include all items, from all users,
	that match your tag. Again, that view might not be what you
	expected. In that case, you can adapt to the group norm, keep
	your tag in a bid to influence the group norm, or both.''
	(Udell, 2004)

	
\par This tight feedback loop leads to a form of asymmetrical
	communication between users through metadata. The users of a
	system are negotiating the meaning of the terms in the
	folksonomy, whether purposefully or not, through their
	individual choices of tags to describe documents for
	themselves.
	

	
\par There are two models to describe what is happening here:
	one that focuses on individual incentives, and one that
	focuses on community aspects.
	
      
      
	\subsection{Individual and Community Aspects}
   
\par Both Delicious
	and Flickr are used by individuals to organize materials with
	their own vocabulary of terms. Individuals have an incentive
	to tag their materials with terms that will help them organize
	their collections in a way that they can find these items
	later. The organizational scheme that emerges for each
	individual reflects their individual information needs. The
	popularity of the ``me'' tag on Flickr perhaps best reflects
	this aspect of a folksonomy, as well as the ``toread'' tag on
	Delicious. Both can really only be understood in the context
	of an individual user.
	
	
\par Conversely, both Delicious and Flickr are services designed
	to share materials. The individual organizational behavior
	takes place in a public virtual space on these web
	sites. Therefore the behavior of the users can also be thought
	of as being influenced and related to their relationship to
	the other individuals using the service, and specific groups
	of users who they share tag use with. It is perhaps harder to
	justify this model simply from examination of the tags used,
	but there is definitely evidence of communication and perhaps
	even community formation through metadata, which will be
	discussed later.
	
	
\par A folksonomy lowers the barriers to cooperation. Groups of
	users do not have to agree on a hierarchy of tags or detailed
	taxonomy, they only need to agree, in a general sense, on the
	``meaning'' of a tag enough to label similar material with terms
	for there to be cooperation and shared value. Although this
	may require a change in vocabulary for some users, it is never
	forced, and as Udell discussed, the tight feedback loop
	provides incentives for this cooperation.
	
	
\par Finally, there is the compulsion to share in general that
	underlies these systems. The very act of user self-‍selecting
	what to tag is important: this is not just material that users
	want to find themselves later, but also material they are
	sharing with others.  Both systems have an explicit kind of
	social networking component built-‍in: Flickr allows you to
	specify other users as contacts, friends, or family and see
	views of just their material; Delicious allows you to
	``subscribe'' to other users lists.
	
	
\par These two models, community and individual motivations, are
	not mutually exclusive, and it is likely both are necessary to
	explain a folksonomy in the context of these services. An area
	of further qualitative analysis could help to determine how
	much each of these theories applies to actual user behavior.
	
      

      
	\subsection{Unanticipated Uses}
   
\par While the folksonomies that
	developed at Flickr and Delicious have a definite focus on
	subject categorization, there are tags being used in some
	unexpected, interesting ways that reflect communication and
	ad-‍hoc group formation facilitated through metadata.
	
	
\par Flickr's ``{\bf sometaithurts}'' - for ``so meta it
	hurts'' is a collection of images regarding Flickr, and people
	using Flickr. (http://www.flickr.com/photos/tags/sometaithurts/)
	The earliest image is of someone discussing social software,
	and then subsequent users posting screenshots of that picture
	within Flickr, and other similarly self-‍referential
	images. The referential and meta nature of the images
	continues as users took pictures of images on Flickr,
	etc. Although this is a playful example, it is a use of tags
	as communicative tool. Only by tagging their photograph with
	``sometaithurts'' could a user of the system join the
	photographic conversation. Conversely, the only way to follow
	the conversation was through the systems automated collocating
	of like tagged items.
	
	
\par A user on Flickr, Andrew Lowosky, began posting pictures of
	doorbells in Florence, along with a brief piece of fiction
	about the doorbell in the description of the photograph. He
	dubbed this combination of photograph and short story
	``{\bf flicktion},'' and tagged it as such. (Lowosky,
	2004.) Some other users have been tagging photographs with
	``flicktion'' and writing short fiction to accompany it,
	although as of November 19, 2004, there were only three other
	users. Although small, there is a quick formation of new terms
	to describe what is going on, and others adopting that term
	and the activity it describes.
	
	
\par Examining all photos in Flickr tagged with
	``{\bf iraq}'' includes photographs Iraq, US troops
	in Iraq, as well as photographs of war protests. Although this
	may not be a community, what we are seeing is a group of
	people helping to define a term with their photographs and
	metadata.
	
      
    
    
      \section{Areas For Further Research}
  
      
	\subsection{Quantitative Tag Analysis}
   
\par Examining the
	quantitative aspects of folksonomies is an area that could
	yield some interesting data on the makeup and use of the terms
	used to describe items. One area to examine is the
	distribution of tag use: I hypothesize that it follows a power
	law scenario. That is, the most used tags are more likely to
	be used by other users since they are more likely to be seen,
	and thus there will be a few tags that are used by a
	substantial number of users, then an order of magnitude more
	tags that are used by fewer users, and another order of
	magnitude more used by only a handful of users. Examining this
	sort of distribution of tag use could give a better indication
	of whether a folksonomy converges on terms and foster
	consensus, or if as the user based grows the vocabulary grows
	at a more even rate, and the distribution of terms flattens,
	perhaps indicating less agreement.
	
      
      
	\subsection{Qualitative User Analysis}
   
\par Examining user behavior
	through ethnographic observation or interview to understand
	user motivations and cognitive processes in tagging items
	would clarify what factors directly influence the formation of
	a folksonomy, and how individual incentives and group
	communication motivations influence use of the
	system. Although it seems that some users are intending to
	facilitate communication through tag use, especially in the
	unintended uses, interviews could make this point
	explicit. Interviews could also elucidate the conscious
	intentions of users in ``normal'' use of the system, which is
	much harder to observe simply from the documents and tags
	themselves. Other behavior that would be helpful to observe is
	the frequency with which users modify or change their tags, or
	future tagging behavior based on the implicit feedback from
	the system in the form of what other documents are tagged with
	a term.
	
      

      
	\subsection{Applicability to other systems}
   
\par Delicious and
	Flickr are large web services designed to organize and share
	digital works. The applicability of user generated free-‍form
	tagging as an organizational construct in other contexts bears
	further investigation. One interesting area would be to
	systems where there is already an existing social network and
	examine how this related to the system. A corporate intranet,
	or a system in an academic setting used by a department's
	faculty and students.
	
	
\par The use of a folksonomy to supplement existing
	classification schemes and provide additional access to
	materials by encouraging and leveraging explicit user metadata
	contributions is a possible area for research and further
	development in information retrieval systems. If information
	retrieval systems begin to incorporate user-‍centered
	information management tools, the organizational schemes
	developed by the users have the possibility to be of great
	interest to other users and improve the systems.
	
      
    

    
      \section{Conclusion}
   
\par A folksonomy represents simultaneously
      some of the best and worst in the organization of
      information. Its uncontrolled nature is fundamentally chaotic,
      suffers from problems of imprecision and ambiguity that well
      developed controlled vocabularies and name authorities
      effectively ameliorate. Conversely, systems employing free-‍form
      tagging that are encouraging users to organize information in
      their own ways are supremely responsive to user needs and
      vocabularies, and involve the users of information actively in
      the organizational system.  Overall, transforming the creation
      of explicit metadata for resources from an isolated,
      professional activity into a shared, communicative activity by
      users is an important development that should be explored and
      considered for future systems development.
      
    

    
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